When do data become publically available?

Data are publically available after the expiration of the data rights of
the principle investigator. By the rules adopted by the international
ROSAT user's committee, this expiration occurs 54 weeks after the completed
data set is shipped from the data center to the PI.

A completed data set is
one that has acquired either

70 percent or more of its allocated exposure
time as good science time,

or one in which no further observations will be
obtained.

The data processing centers at GSFC and MPE have sole
responsibility for determining when a data set
is to be made available to the public.

Another important aspect to the question of data availability is the
physical transfer of data to the public archive. In the US, this transfer
means the moving of data from the US data processing center's private
archive to the HEASARC public archive. ROSAT data that has been processed at
the US data processing center typically enters the HEASARC archive within
two weeks of its scheduled public release date.

The movement of German and UK data processed at MPE is more complicated.
For these data, data tapes are sent from MPE to the US, where the data
tapes must first be ingested into the US data center's private archive
before being staged to the NDADS public archive. This is a longer process,
which means that there can be a delay in access to public German and UK
data from the US archive. This delay is typically about a month, although
we are working to minimize this delay as much as possible. There is a
similar delay in access to US data from the MPE and UK archives for exactly
the same reason.